The present invention relates to an endodontic instrument and more particularly to an endodontic cutting instrument which is manually manipulated to clean and enlarge the root canals of teeth.
Generally there are three types of such instruments in use. First, there is an endodontic file or K-file which is substantially a square ground tapered rod which is axially twisted to form the instrument. Twisting provides the instrument with four spiral cutting edges. This instrument is generally considered to be the strongest of the three types and is used as a file wherein it is inserted into the root canal and axially reciprocated to remove pulp from the root canal.
The second type is substantially a triangular ground tapered rod. This rod, too, is twisted to form the instrument wherein twisting provides the instrument with three spiral cutting edges. This instrument is generally considered to be the best cutting instrument and is used primarily as a reamer wherein it is inserted into the root canal and twisted to ream or enlarge the canal.
The third type of instrument is a Hedstrom file. The Hedstrom file is a cylindrically tapered rod which is fluted by grinding along the taper in a helical pattern to form the finished instrument. The Hedstrom file is generally considered to be the weakest of the three instruments but it is also considered to have the best debris removal characteristics of the three types.
Each of these three types of instruments represents a compromise from an ideal instrument. For example, the K-file or square shaped instrument is strong, but has poorer cutting characteristics than the triangular shaped instrument and does not have the debris removal characteristics of the Hedstrom file. The reamer or triangular shaped instrument has good cutting characteristics, but is not as strong as the K-file and does not have the debris removal characteristics of the Hedstrom file. The Hedstrom file has the best debris removal characteristics of the three instruments and a cutting ability between the square and triangular, but is the weakest of the three instruments.
The endodontic instrument of the present invention, however, combines the best features of each of the three standard types and provides an instrument which is strong, has good cutting characteristics and good debris removal characteristics.